WPT details: WebGPU/WGSL have a conformance test suite (https://github.com/gpuweb/cts) that is regularly pulled into Chromium and part of the testing of Dawn/Tint in Chromium.
WebGPU now allows developers to omit entry points to shader modules when creating a pipeline, improving ergonomics. If no default entry point is found, a GPUValidationError will be triggered as usual.